These tests were split off angle_end2end_tests (which are now black box),
so this restores them back to running on the bots.

Run only on Windows bots, as for now this is the only platform
which has white box tests, and running 0 tests is considered a failure
by some platforms (i.e. Android).

BUG=691136
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2689873002
Cr-Commit-Position: refs/heads/master@{#450975}